Self-swarming robots that exploit hydrodynamical interaction

Although numerous swarm robotic systems have already been developed, they have exhibited limited adaptability. This was partly because the previous researchers designed the control schemes on the basis of informational interaction, without considering the physical effects of the environment. To tackle this problem, we employ an unconventional approach: we design a control scheme for swarm robots based on their physical interaction in a hydrodynamic field, inspired by biological swarming. Through simulations using a smoothed particle hydrodynamics method, we show that the proposed control scheme allows agents to form an ordered swarm in response to their environment.     

关于雷达回波延迟时间的推导

与一般文献推导雷达回波的延迟时间完全不同,首先通过对兰州大学段一士先生推出的光线在恒星附近的轨道方程的求解,再利用所求的求解结果,重新推出了雷达回波延迟的时间。     

Effects of layup sequences on stresses of thick composite cantilever tubes

In this study, a new simple-input displacement-based method is used to study effects of layup sequences on stresses, strains, and deformations of thick laminated orthotropic cantilever straight tubes under transverse loading. Three-dimensional stress distributions are obtained based on the most general displacement field of elasticity. A layer-wise theory which includes the full three-dimensional constitutive relations is used. A non-dimensional simple coefficient is introduced to compare interlaminar radial stresses of different layup sequences. Finally, some design guidelines are proposed to consider effects of layup sequences of laminated thick composite tubes subjected to shearing load.     

An exploratory study of the relationship between construction workforce physical strain and task level productivity

The monitoring of construction workforce physical strain can be a valuable management strategy in improving workforce productivity, safety, health, and quality of work. Nevertheless, clear relationships between workforce performance and physical strain have yet to be established. An exploratory investigation of the relationship between task level productivity and physical strain was conducted. Nine participants individually performed a four-hour simulated construction task while a wearable physiological status monitor continuously assessed their physiological condition. Heart rate, relative heart rate, and breathing rate were utilized as predictors of physical strain, and task level–single factor productivity was used as an index of productivity. Numerous regression models were generated using the collected data. This investigation initially unsuccessfully attempted to establish a relationship between physiological condition and productivity at the individual worker level. However, an analysis of the regression models showed that there is a relationship between productivity and either heart rate or relative heart rate at the group level, and that this relationship is parabolic. Breathing rate was proved to not be a significant predictor of productivity. Research results significantly improve understanding of the relationship between work physiology and task productivity. Researchers and practitioners may use the tested monitoring devices, analysis methods, and results to design further applied studies and to improve workforce productivity.     

Development of a helicon-wave excited plasma facility with high magnetic field for plasma-wall interactions studies

The high magnetic field helicon experiment system is a helicon wave plasma(HWP)source device in a high axial magnetic field(B_0)developed for plasma–wall interactions studies for fusion reactors.This HWP was realized at low pressure(5?×?10~(-3)?-?10 Pa)and a RF(radio frequency,13.56 MHz)power(maximum power of 2 k W)using an internal right helical antenna(5 cm in diameter by 18 cm long)with a maximum B_0of 6300 G.Ar HWP with electron density~10~(18)–10~(20)m~(-3)and electron temperature~4–7 e V was produced at high B_0 of 5100 G,with an RF power of 1500 W.Maximum Ar~+ion flux of 7.8?×?10~(23)m~(-2)s~(-1)with a bright blue core plasma was obtained at a high B_0 of 2700 G and an RF power of 1500 W without bias.Plasma energy and mass spectrometer studies indicate that Ar~+ion-beams of 40.1 eV are formed,which are supersonic(~3.1c_s).The effect of Ar HWP discharge cleaning on the wall conditioning are investigated by using the mass spectrometry.And the consequent plasma parameters will result in favorable wall conditioning with a removal rate of 1.1?×?10~(24)N_2/m~2 h.     

Study of vortex in flow fields induced by surface dielectric barrier discharge actuator at low pressure based on Q criterion

Flow fields induced by a surface dielectric barrier discharge actuator at low pressure of 7 kPa are measured by particle image velocimetry.The distribution of local vortices in the flow field is revealed by the Q criterion.The reason for the generation of vortices is analyzed and the influence of pulse frequency and duty cycle on vortices is studied.The results show that the Q criterion can reveal the small-scale vortices,which cannot be indicated by the streamline.The direction transition zone where the induced jet moves from the vertical to the tangential and the shear layer between the jet and stationary air are prone to the generation of strong vortices.The influence of pulse frequency on vortices is not obvious,but the variation of duty cycle can significantly affect the strength and distribution of vortices.     

谈建筑的场地环境对方案设计的影响

解释了场地环境设计的含义,阐述了场地和环境包含的两个不同层面的问题——场地的图形和场地的环境特质,并结合实例,分析了建筑的场地环境对方案设计的影响,以供参考。     

Innovative Work Behaviour: The Impact of Comprehensive HR System Perceptions and the Role of Work–Life Conflict

Human resource (HR) systems have the potential to both foster innovative work behaviour (IWB) and reduce work–life conflict (WLC)—enabling employees to engage in IWB. We investigate the proposed relationships between comprehensive HR systems, WLC and IWB using variance-based structural equation modelling. We found that HR systems that are perceived as comprehensive significantly enhance IWB and decrease feelings of WLC. Contrary to our expectation, we found a significant yet positive effect of WLC on IWB. Employees may respond to WLC constructively by being innovative, improving their environment and making the work–life interface manageable. By promoting IWB, HR systems might also help employees to deal with residual—and, perhaps, unavoidable—levels of WLC.     

强化环境监测管制工作的思考

现今社会正处在环境监测管制的改革创新阶段，所以强化环境监测管制工作势在必行。着重分析了环境监测管制工作的特点，提出了现实环境所面临的一些问题，并对此问题提供了一些对策。